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So.. is there any real MPG improvement in weight saving?

Discussion in 'Gen 3 Prius Accessories and Modifications' started by cyclopathic, Apr 25, 2011.

  1. cyclopathic

    cyclopathic Senior Member

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  2. ZitterZap

    ZitterZap Member

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  3. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    +1

    That's close to what I've noticed when fully loaded.
     
  4. Corwyn

    Corwyn Energy Curmudgeon

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    Weight savings have the most impact when the car is braking. Calculating based on fixed speed will understate the importance of weight. How close it will be to your actual mileage depends on your routes.
     
  5. mmcdonal

    mmcdonal Active Member

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    Wouldn't it be acceleration and braking? Also, the time you have the throttle more than closed, you have to use more fuel to get/keep the car to the speed you want. Also, as quickly as you want.

    Assuming you are braking on the flat, wouldn't it take longer to stop, and therefore get more regen?

    Anyway, I agree, the lighter the vehicle the better. EcoModders don't even like to fill up till they are on fumes since they are trying to consume the most fuel / weight. Some may even only half fill the tank.
     
  6. sipnfuel

    sipnfuel New Member

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    Carrying about 400 lb of extra weight dropped my mpg about 5-8. Wasn't able to glide or use SHM effectively.
     
  7. GrumpyCabbie

    GrumpyCabbie Senior Member

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    5-8 mpg? Eeek, I'd better start that diet :eek:
     
  8. SlowTurd

    SlowTurd I LIKE PRIUS'S

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    just pick up midgets
     
  9. sipnfuel

    sipnfuel New Member

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    LOL ... well this is from about 58 mpg to 53-50 mpg. When the fuel saving techniques are more extreme, the inability to use them drops fuel economy back down to normal levels.

    I tried, but midgets are afraid of the Prius. Something about being closer to the electromagnetic radiation.
     
  10. Corwyn

    Corwyn Energy Curmudgeon

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    The braking is where the irretrievable energy loss comes from. Accelerating just turn chemical energy into kinetic energy (at a slight efficiency loss). Braking throws it away as heat. Regenerative braking gets some portion of that back as chemical, of course. You could claim that accelerating commits you to eventually braking, I wouldn't argue.

    The greater your cars mass, the more force is required to accelerate it (or decelerate it). That force is what you are getting back when you regeneratively brake. If you have ample space to brake slowly, you only lose the increased momentum in the 7 to 0 mph range. If not, you are more quickly out of the 100% regen braking realm.
     
  11. cyclopathic

    cyclopathic Senior Member

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    just for comparison:

    reducing rolling resistance by 30% (typical better "green" tire) will improve MPG by 12.7% at 60MPH, 18.3% at 45MPH.

    cost of new green tires ~450$
    green tire premium over regular tires ~100$ (25$ per tire).

    cost to make car 200lbs lighter ....
     
  12. Judgeless

    Judgeless Senior Member

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    I notice the differnce when I have other people in the car.
     
  13. nickfromny

    nickfromny Member since 2007

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    Power to Weight ratio, the oldest measure of a performance machine. British battle ships put copper bottoms on their hulls to keep barnacles off a few hundred years ago. This made there ships fast while adding weight. This is one example of imporving performance without lowering weight. So if we wax our car & keep it clean we should see improved MPG?? Same prinicpal for getting lower rolling resitance tires/ over inflating them to at least 42f/40r to get better MPG while not loweriing the weight of car. Both ideas have helped other machines in past.